I assume you mean the charger is putting out 17v, and that's way too much.  The charger is bad.  Charging voltage should be 13.8 to 14.4 depending on amount of discharge, and charge intermittently when maintaining.  Try disconnecting the battery from the loads and read the charging voltage across the terminals when the charger is hooked up to it. You might also have the battery tested because over charging can damage it.

Stuart

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of WILLIAM WITZ
Sent: Thursday, March 03, 2016 4:09 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Voltage Question

I have a nice 12 V. Battery charger that I use on my Vanagon. The little muffin fan died I replaced with a another 12V. ball bearing fan but the power supply to said fan is putting out 17 V. how long do think said fan will last under these conditions? Over the last 10 years i have become fond of this battery charger is it time to let go? The charger itself seems to be working fine.Thanks, Bill Witz 84 Westy Tiico